A DNA sequencer is a device that determines an order of the nucleotide bases (adenine, guanine, cytosine, and thymine) in a DNA strand. One DNA sequencer sequences DNA strands carried on a biochip, a lab-on-a-chip, or the like that has a plurality of sample processing regions and micro-channels that go to, from and/or between the sample processing regions. The biochip also includes an interface to a manifold of the sequencer for receiving fluids such as reagents, wash solutions, primers, dyes, etc., and for interfacing with a fluid and sample moving sub-system such as a high-pressure sub-system.
Generally, the DNA strand is moved or advanced under high pressure from a sample processing region to a sample processing region and is processed at each of the sample processing regions. By way of example, with one DNA sequencer, a sample such as a bucchal swab, including a DNA strand, is first processed at an extraction region of the biochip with an extraction sub-system that extracts one or more DNA strands from the sample. An extraction fluid such as a lyses reagent is routed to the region via the micro-channels. The DNA strand is then moved to a purification region of the biochip where a purification sub-system purifies the extracted DNA strand. A purification fluid such as a wash solution is routed to the region via the micro-channels.
The DNA strand is then moved to a replication (thermocycling amplification) region of the biochip where the DNA strand is replicated and labeled, e.g., via polymerase chain reaction (PCR) or otherwise by a replication sub-system. Replication and labeling fluids such as a primer and fluorescent dyes are routed to the region via the micro-channels. The DNA strand is then moved to a separation and analysis region of the biochip where a separation sub-system separates the nucleotides, e.g., via capillary electrophoresis or otherwise, and an analysis sub-system sequences the nucleotides, e.g., via an optical detection system. Sequencing has been determined based on dye wavelength, and a signal indicative of the sequence is read out.
One automated DNA sequencer has integrated the above-noted processing sub-systems into a single device. With this sequencer, the biochip is placed in a single test position, and each of the sub-systems sequentially processes the biochip at the test position. The biochip includes the necessary infrastructure (micro-channels, processing regions, etc.) to concurrently interface all of the processing sub-systems and a manifold of the sequencer, which provides the various fluids for the processing and high pressure for moving the DNA strand through the biochip from processing region to processing region. Unfortunately, such a DNA sequencer requires a relatively large number and complex arrangement of micro-channels, valves, interfaces, etc., at the manifold.
With this sequencer, a single biochip is loaded and processed at any given time. A human or machine loads the biochip for processing and unloads the biochip after processing. As a consequence of the foregoing, biochip-to-biochip processing can be a relatively lengthy and slow process. A trend has been to utilize a DNA sequencer configured to individually process, in parallel, multiple samples carried on a single biochip. Although this technique may increase the number of samples processed during a given time frame, biochip-to-biochip processing still remains a relatively lengthy and slow process. For example, in both instances, the processing time for the first biochip is equal to the aggregate of the processing time of each processing sub-system, and the processing time for each successive biochip, relative to the processing time for a preceding biochip, is also equal to the aggregate of the processing time of each processing sub-system.